Radio frequency over glass system with radio frequency over glass fiber extender

ABSTRACT

The present disclosure provide for a radio frequency over glass (RFoG) system having an optical node and an RFoG extender residing in a first service area coupled to the optical node. The RFoG functions to transmit an upstream (US) radio frequency (RF) signal to a head end, receive a downstream (DS) RF signal from the head end and extend the DS RF signal to the second service area. The second service area is different from the first service area and the second service area is remote from the first service area.

TECHNICAL FIELD

The present disclosure relates to a field of hybrid fiber coax (HFC)network. More particularly, examples relate to implementations with aradio frequency over glass (RFoG) extender at one of a customer premiseequipment (CPE) or a multi-dwelling unit (MDU) CPE in a RFoG system toextend network coverage to another CPE (remote from the CPE) or anotherMDU CPE (remote from the MDU CPE).

BACKGROUND

The Hybrid Fiber-Coax (HFC) network has continuously evolved to deployfiber deeper. It is foreseen that in the near future, it will become aFiber to the Premise (FTTP) or Fiber to the Home (FTTH) network. One ofthe technologies in consideration to allow this transition is RadioFrequency over Glass (RFoG). RFoG is a deep-fiber network design inwhich the coax portion of the hybrid fiber coax (HFC) network isreplaced by a single-fiber passive optical network (PON). in order todeliver cable services through the passive optical network (PON) styleFTTP network infrastructure. PON is a telecommunications technology thatimplements a point-to-multipoint architecture, in which unpowered fiberoptic splitters are used to enable a single optical fiber to servemultiple end-points such as customers, without having to provisionindividual fibers between the hub and customer. The RFoG system isdefined to begin where the network becomes passive, extending from thatpoint to the customer premise (CPE). This interface is referred to asthe optical node. The CPE is a service provider equipment that islocated on the customer's premises (physical location) rather than onthe provider's premises or in between. Some examples of the CPE include,but not limited telephone handsets, cable TV set-top boxes, and digitalsubscriber line routers. The RFoG system is defined to terminate at thesubscriber-side interface of an RFoG Optical Network Unit (R-ONU) orcustomer premise equipment (CPE) at the home. An optical network is ameans of communication that uses signals encoded onto light to transmitinformation among various nodes of a telecommunications network.

As part of the continuous effort to converge towards next-generationnetworks (NGN), the RFoG has been designed to share trunk fibers withthe traditional Passive Optical Network (PON). A RFoG implementationthat supports the data over cable services interface specification(DOCSIS) RF infrastructure along with traditional PON has beenconsidered as the truly Hybrid PON (HPON) architecture. HPON enablesother fiber deep technologies such as Fiber to the Curb (FTTC), Fiber tothe Multiple Dwelling Unit (FTT-MDU), and fiber to the deep node (N+0).As HPON becomes popular as a network capable to provide higher amountsof bandwidth than legacy HFC, and as it becomes commercially attractivefor operators, the increasing demand of network coverage is driving newrequirements for key enabling products. It is the case when the fiberlinks from the hubs to the optical nodes are very long distances. Evenwhen some operators were careful to deploy enough nodes to assure thatthe vast majority of the fiber distances were 20 km or less (e.g. PONservices). Other operators allowed much longer fiber distances (˜60 km)to be used (e.g. RFoG). The long fiber distances in these HPON networksnegatively impacts the available performance budget and makes itdifficult to further increase network coverage. In addition, there areother difficulties such as the limited number of trunk fibers, and thewavelength congestion at each fiber. For the latter, it is worth notingthat HPON networks are required to operate at specific wavelengths for aDownstream (DS) and an Upstream (US) in order to allow coexistencebetween PON and RFoG services. Therefore, it is not possible to operatemore than one service (RFoG+PON) group on the same trunk fiber at thesame time.

In case of PON systems, in order to accommodate the long distances andlimited numbers of fibers, many operators are deploying PON extenders.The PON extender is an active device in the node that regenerates theelectrical signals so that they can be retransmitted to the localserving area with high fidelity, eliminating the penalty of long linkbudgets between hubs and nodes. On the other hand, for RFoG services, EPpatent publication number EP1235434 B1 describes a “dual broadbandoptoelectronic repeater” which makes it possible to use the networktopology of the point-to-point type from the node to each individualsubscriber to extend the performance budget. The EP 1235434 proposes toeliminate branches between the CPE and the final optical transmitter orreceiver in the dual broadband optoelectronic repeater. However, theaforementioned repeater presents several disadvantages in terms of costeffectiveness, power consumption, coverage and capacity. In the forward(a.k.a. downstream) path, receiving, amplifying and retransmission of DSsignals with one laser per subscriber increases considerable cost andpower dissipation. In addition, since the repeater is proposed at thenode location, it still presents link budget limitation when the networkcoverage increase is required further away from the node's service area.

An example of a RFoG architecture 100 is illustrated in FIG. 1 when anetwork coverage extension is needed from a first service area 108 toanother new remote service area (second service area) 110. An opticalnode 104 depicted in FIG. 1 is an active RFoG node. The RFoG node isused for fiber deep applications, where service areas (first service are108 and second service area 110) are connected via optical fiber to thenode. In the implementation, as shown in FIG. 1, the conversion ofoptical/electrical for DS signals and the conversion ofelectrical/optical for US signals occur at the service area location inthe MDU. The optical node 104 is optically coupled to a head end 102. Ahead end includes multiple devices for delivery of video and dataservices including EdgeQAMS (EQAMs) for video, cable modem terminationsystems (CMTS) for data, and other processing devices for control andmanagement. These systems are connected to multiple fiber optic cablesthat go to various neighborhood locations. A fiber optic neighborhoodnode is located between each fiber optic cable and a corresponding trunkcable which in turn is interconnected to the homes through branchnetworks and feeder cables. Because the trunk cable, as well as thebranch networks and feeder cables, each propagate RF signals usingcoaxial cable, HFC nodes (preferably located in the MDU) are used toconvert the optical signals to electrical signals that can betransmitted through a coaxial medium, i.e. copper wire to be distributedat homes. The optical node 104 of FIG. 1, as discussed above is anactive RFoG node transmits and receives optical signals from the headend 102 and to MDUs. Similarly, when electrical signals from the homereach the node over the coaxial medium, those signals are converted tooptical signals and transmitted across the fiber optic cables back tothe systems at the head end. Accordingly, a head end is a control systemthat receives RF signals for processing and distribution over a cabletelevision system. Specifically, the head end receives the RF signalscontaining data signals, multiplexes them using a RF combining network,converts the combined RF signal to an optical signal and outputs theoutput signal. The combined and converted RF signals comprise adownstream (DS) signal, which refers to a signal transmitted from thehead end 102 to the optical node 104 to an end user via a network(example, coaxial network, local network, etc.). In the upstream (US)direction, the combined and converted RF signals comprise a (US) signal,which refers to a signal transmitted from the end user to the head end102. The optical node 104 functions to extract the traditional cablesignals such as the DS signal having the wavelength of 1550 nm and theUS signal having the wavelength of 1610 nm. The traditional cablesignals are processed to be sent to the first service area 108 and tothe second service area 110. The optical node 104 is also coupled to aPON unit 106 to provide cable services to PON network (not shown). Someexamples of a PON network include Broadband PON, Gigabit PON, EthernetPON. In the scenario presented in FIG. 1, it is assumed that a multipledwelling unit (MDU) in the first service area 108 contains multiple MDUCPEs 112 a-112 n. However, network coverage increase can apply in otherscenarios, such as but not limited to service areas where each user hasdirect fiber connection to home with independent CPEs connected directlyto the optical node 104. As shown in FIG. 1, is an RFoG network coverageto the first service area 108 (distance=FLn-1(a)). A typical way toincrease coverage in the RFoG network, is the introduction of expensivelow-distortion optical amplifiers, extra optical splitting, and externaldispersion compensation modules at the optical node 106 to achieve agood quality signal at longer distances in order to service additionalremote areas (distance=FLn-1(a)+FLn-1 (b) from FIG. 1). However, thisimplementation only provides budget performance extension for theforward or the downstream (DS), and the return or upstream (US) stillsuffers poor signal quality. On the other hand, an extra optical fiberfrom the optical node 104 to the second service area 110 is required.Therefore, in most of the cases, it may be preferable to install anotherremote node at a location closer to the second service area 110 in orderto increase network coverage. This approach includes the necessity toinstall new fiber links all the way down from the Head End 102 to thenew node and to a MDU CPE 114 in the second service area 110.

FIGS. 2A and 2B illustrate a schematic diagram of conventional MDU CPEdevices 200 and 240 respectively typically used by the cable operatorsto provide both traditional cable service and PON service on RFoG systemexpanded to support PON architecture and services. Specifically, FIG. 2Adepicts a conventional MDU CPE device 200 over RFoG architecture with anoption to upgrade to a PON optical network unit (ONU) outside of the MDUCPE and FIG. 2B depicts a conventional MDU CPE device 240 over RFoGarchitecture including the PON ONU integrated into the same MDU CPEdevice. In one example, there is shown an RFoG wavelength divisionmultiplexer (WDM) filter 204 optically coupled to a head end 202. Asdiscussed above, a Head End is a control system that receives data (suchas television, internet, voice etc.) signals for processing anddistribution over a cable television system. The RFoG WDM filter 204functions similar to the optical node 104 of FIG. 1 such that the firstoptical filter 104 extracts the traditional cable signals (DS opticalsignal having the wavelength of 1550 nm and US optical signal having thewavelength of 1610 nm). As such, the RFoG WDM filter 204 functions toseparate the DS optical signal from the US optical signal. The RFoG WDMfilter 204 transmits the DS optical signal to a first RFoG opticalreceiver (RFoG optical RX1) 206, which converts the DS optical signalinto RF domain into a DSRF signal containing data. The RFoG optical RX1206 sends the DSRF signal to a diplexer 210. Data may flow not only fromthe head end 102 to a MDU coaxial network 212 to reach the variousneighborhoods, but also from the MDU coaxial network 212 to the head end102, In order to provide this functionality, typically one spectrum offrequencies are dedicated to deliver forward (DS) path signals from thehead end 102 to a MDU coaxial network 212 to reach the variousneighborhood locations and another (typically much smaller) spectrum offrequencies are dedicated to deliver return (US) path signals from theMDU coaxial network 212 to the head end 102. The diplexer 210 providessuch functionality. Specifically, the diplexer 210 includes two or moreband pass filters to separate the forward (DS) path signals from thereturn (US) path signals, and separately amplifies the signals from eachrespective direction in their associated frequency range. The diplexer210 includes a high frequency filter 210 a and a low frequency filter210 b. As such, the DSRF signal is filtered in the high frequency modeof the diplexer 210 and the filtered DSRF signal is outputted to the MDUcoaxial network 212 for connection to different users. The diplexer 210receives the USRF signal from the MDU coaxial network in the lowfrequency mode and transmits to the analog driver 214. In one example,the analog driver 214 is an RF amplifier which functions to convert alower power radio frequency signal into a higher power radio frequencysignal. As such, the analog driver 214 increases the power of the USRFsignal. The analog driver 214 transmits the USRF signal to a first RFoGoptical transmitter (RFoG optical TX1) 208, which converts it back intothe optical domain to an US optical signal and transmits to the RFoG WDMfilter 204 to be transmitted to head end 202. As shown in FIG. 2A is afirst link from the RFoG WDM filter 204 to couple with a local PONnetwork (not shown) as an option to upgrade to PON cable services via aPON located outside of the MDU CPE device 200.

FIG. 2B shows a PON extender 241 integrated within the MDU CPE device240 to extend PON cable services such that one MDU may support both thetraditional cable service (Coaxial) and the PON cable service. The PONextender 241 includes a PON optical unit (ONU) 242, a PON WDM filter244, a first PON optical receiver (PON optical RX1) 246, and a first PONoptical transmitter (PON optical TX1) 248 and a digital driver 250. APON ONU may be a gigabit PON (GPON or gigabit Ethernet PON (GEPON) chipsets. The PON WDM filter 244, extracts the PON services (DS PON opticalsignal having the wavelength of 1490 nm and US PON optical signal havingthe wavelength of 1310 nm) received from the head end 202. The PON WDMfilter 244 transmits the DS PON optical signal to the PON optical RX1246, which converts the DS PON optical signal into RF domain into a DSRFPON signal containing data, which is transmitted to the PON ONU 242. ThePON ONU 242 is an active device that regenerates the RF signals in orderto be retransmitted to a local PON network 252. As such the regeneratedDSRF PON signal containing data is outputted from the PON ONU 242 to thelocal PON network 252 to different users. The PON ONU 242 receives theUSRF PON signal via the PON local network 252 and transmits it to thedigital driver 250, which functions to convert a lower power RF signalinto a higher power RF signal. As such, the digital driver 250 increasesthe power of the USRF PON signal. The digital driver 250 transmits theUSRF PON signal to the RFoG optical TX1248, which converts it back intothe optical domain to US optical signal and transmits the US PON opticalsignal to the PON WDM filter 244 to be transmitted to Head End 202.

The conventional MDU CPEs as described above with respect to FIGS. 2Aand 2B are limited to provide RFoG network coverage to one service areaand thus do not accommodate the increasing demand of extending the RFoGnetwork coverage to other remote service areas without the need to addmore optical fibers and amplifiers (as discussed above with respect toFIG. 1), which results in increase in cost, power consumption, coverageand capacity of the RFoG network.

SUMMARY

The present disclosure describes a RFoG architecture with a RFoGextender, which provides capabilities to provide RFoG network coveragenot only into a MDU CPE located in a service area but also extends RFoGnetwork coverage to one or more new service areas, which are remote fromthe service area.

According to one implementation, the RFoG system includes an opticalnode and an RFoG extender residing in a first service area and coupledto the optical node. The RFoG extender transmits an upstream (US) radiofrequency (RF) signal to a head end and receives a downstream (DS) RFsignal from the head end. The RFoG extender extends the DSRF signal tothe second service area, which is different and remote from the firstservice area. The RFoG extender located at the first service area alsoextends the USRF signal from the second service area to the head end.

According to another implementation, the RFoG system includes an opticalnode and an RFoG extender residing in a first area and coupled to theoptical node. The RFoG extender transmits an upstream (US) radiofrequency (RF) signal to a head end and receives a downstream (DS) RFsignal from the head end. The RFoG extender extends the DSRF signal tothe second service area, which is different and remote from the firstservice area. The RFoG system in this example also includes a passiveoptical network (PON) extender that resides in the first service areaand is coupled to the optical node. The PON extender transmits a US PONsignal to a local PON network, receives a DS PON network from the localPON network, extends the DS PON signal to the second service area andextends the US PON signal from the second service area to the head end.

Additional objects, advantages and novel features of the examples willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing and the accompanying drawings or may be learned by productionor operation of the examples. The objects and advantages of the presentsubject matter may be realized and attained by means of themethodologies, instrumentalities and combinations particularly pointedout in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations by way of exampleonly, not by way of limitations. In the figures, like reference numeralscan refer to the same or similar elements. According to common practice,the various features of the drawings are not drawn to the scale. Also,the dimensions of the various features may be arbitrarily expanded orreduced for clarity. Included in the drawings are the following figures:

FIG. 1 depicts a conventional radio frequency over glass (RFoG)architecture.

FIG. 2A shows a conventional MDU CPE device.

FIG. 2B illustrates a conventional MDU CPE device with integration of aPON extender.

FIG. 3 depicts an example of an RFoG architecture having an RFoGextender.

FIG. 4A shows an example of a MDU CPE device.

FIG. 4B illustrates an example of a MDU CPE device with an integrationof a PON extender.

FIG. 5A depicts a flow chart illustrating radio frequency (RF)processing of a full RF load of a downstream signal.

FIG. 5B shows a flow chart illustrating radio frequency (RF) processingof a channel segmentation of a RF load of the downstream signal inaccordance with another example of the present disclosure.

FIG. 6A illustrates an RFoG architecture of a full RF load of thedownstream signal in accordance with an example of the presentdisclosure.

FIG. 6B illustrates an RFoG architecture of a channel segmentation of aRF load of the downstream signal in accordance with another example ofthe present disclosure.

FIG. 7 illustrates a block diagram of a customer premises equipment(CPE) RFoG architecture 700 of a full RF load of the DS signal and thechannel segmentation of the RF load of the DS signal in accordance withan example of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and/or circuitry have been described at a relatively high level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

FIG. 3 depicts an example of a block diagram of an RFoG architecture300. The RFoG architecture 300 is similar to the RFoG architecture 100of FIG. 1 as described above with an exception that at least one MDU CPEamong a plurality of MDU CPE 312 a-MDU CPE 312 n includes at least oneRFoG extender 330. In the example shown in FIG. 3, the MDU CPE 312 dincludes the RFoG extender 330. Although, only one MDU CPE 312 d isshown to include the RFoG extender 330, other MDU CPEs 312 a-c and MDUCPEs 312 d-n may also include the RFoG extender 330. Also, the RFoGextender 330 is shown to be implemented in the MDU CPE of the firstservice area 308 as illustrated in FIG. 3, however, the RFoG extender330 may be implemented in the MDU CPE (for example, the MDU CPE 314) ofthe second service area 310. Furthermore, even though the RFoGarchitecture includes MDU CPE in the first service and the secondservice area, a CPE may be implemented in the first and the secondservice area with an RFoG extender in the CPE of one of the first or thesecond service area. An optical node 304 is also coupled to a PON unit306 to provide data services to a PON network (not shown).

The RFoG extender 330 functions to provide cable services (bothtraditional service and PON service) to the customers in the firstservice area 308 and serves to extend the cable services from the firstservice area 308 to the second service area 310, which is remote fromthe first service area 308. As shown, the RFoG extender 330 can servecustomers in the first service area 308, and it can also provide anoptical link (input/output) 309 to serve one or more customers in thesecond service area 310. In one implementation, the optical input/outputis provided via an optical link, such as a fiber added between theMDUCPE 312 d including the RFoG extender 330 of the first service area308 and the MDU CPE 314 of the second service area 310 to extend the DSsignal to the second service area 310. Similar to the other MDU CPEs 312a-c and MDUCPE 312 e-n, the MDU CPE 312 d with the RFoG extender 330 isoptically coupled to the optical node 304 to receive the downstream (DS)signal from the optical node 304 and to send the upstream (US) signal tothe optical node 304. The MDU CPE 313 d with the RFoG extender 330 isalso coupled to send the DS signal to MDU CPE 314 of the second servicearea 310. In one implementation, the MDU CPE 312 d with the RFoGextender 330 is also coupled to receive the US signal from the MDU CPE314 of the second service area 310. As such, the RFoG extender in thefirst service area 308 extends the US signal from the second servicearea 310 to the head end 302. The details of the RFoG extender 330 areprovided herein below.

FIG. 4A depicts an example of a schematic diagram of a MDU CPE device400. The MDU CPE device 400 is similar to the MDU CPE device 200 asillustrated in FIG. 2A with the exception that the MDU CPE device 400includes at least one RFoG extender 430. The RFoG extender 430 includesa first RF splitter 416, a downstream radio frequency (DSRF)conditioning circuit 418, an upstream radio frequency (USRF)conditioning circuit 420, a RFoG extender optical TX 422, a RFoGextender optical RX 424, and a RFoG extender WDM filter 426. In oneimplementation, the RFoG extender 430 functions as a RFoG extension toprocess and extend the DS signal from a first service area (for example,the first service area 308 in FIG. 3) to a second service area, which isremote from the first service area (for example, the second service area310 in FIG. 3) as described in greater detail below. In anotherimplementation, the RFoG extender 430 functions as a RFoG extension atthe first service area 308 to process and extend the US signal from thesecond service area (for example, the second service area 310 in FIG. 3)to the head end (for example, the head end 302 in FIG. 3) as describedin greater detail below.

A RFoG WDM filter 404 is optically coupled to an optical node (notshown) which connects to a head end 202 and extracts the traditionalcable services (DS optical signal having the wavelength of 1550 nm andUS optical signal having the wavelength of 1610 nm). The RFoG WDM filter404 transmits the DS optical signal to an RFoG optical RX1406, whichconverts the DS optical signal into an RF domain resulting in a DSRFsignal 403′ containing data and transmits to the analog driver 414. Inone example, the analog driver is an RF amplifier, which functions toincrease the power of the DSRF signal resulting in a DSRF signal 403 Theanalog driver 414 transmits the DSRF signal 403 to the first radiofrequency (RF) splitter 416, which separates the DSRF signal 403 intotwo separate DSRF signals such as a first DSRF signal 403 a and a secondDSRF signal 403 b. In one implementation, the DSRF signal 403 (output ofthe analog driver 414) is equally separated such that the first DSRFsignal 403 a contains fifty percent of the DSRF signal 403 and thesecond DSRF signal 403 b also contains the fifty percent of the DSRFsignal 403. Although, the implementation as described equally separatesthe DSRF signal, the DS signal may be unequally split into two separatesignals as per configuration requirements of the analog driver 414. Thefirst DS RF signal 403 a is transmitted to the diplexer 410, whichfilters the first DSRF signal 403 a in high frequency mode and outputs afiltered DSRF signal 403 to a MDU coaxial network 412 for connection todifferent users.

The second DSRF signal 403 b is transmitted into the DSRF conditioningcircuit 418, which functions to process full RF load of the second DSRFsignal 403 b. In one implementation, the DSRF conditioning circuit 418functions to multiplex all the DSRF signals, maintain stable gain of theRF path, equalizes the DSRF signal to flatten the RF gain over theentire DS RF bandwidth, attenuates to control RF gain over the link,improves signal quality and compensates for fiber dispersion andstimulate brillouin scattering (SBS)) suppression to reduce fibernon-linearity. The DSRF conditioning unit 418 may also filter outdesired channels and down convert the desired channels. In oneimplementation, the DSRF conditioning circuit 418 may be designed fordirect modulation (such as multi-carrier modulation techniques, e.g.orthogonal frequency division multiplexing (OFDM)) or for externalmodulation with a difference residing in the pre-distortion and the biasconnections for the external modulation. The DSRF conditioning circuit418 may further function to condition the modulated signal into a formatthat can be sent through the network.

In one implementation, the DSRF conditioning circuit 418 processes acomplete full RF load of the second DS RF signal 403 b as described infurther detail below with respect to FIG. 5A. In another implementation,the DSRF conditioning circuit 418 processes a channel segmentation RFload of the second DSRF signal 403 b as described in greater detailherein below with respect to FIG. 5B.

FIG. 5A is a flow chart 500 illustrating one implementation of RFprocessing 500 of the DSRF conditioning circuit 418 performed on a fullRF load of the second DSRF signal 403 b of FIGS. 4A and 4B. In oneimplementation, the RF processing 500 is programmable over the DSRFconditioning unit 418 . . . . In one implementation, the full RF load ofthe second DSRF signal includes broadcast and narrowcast channels. Thebroadcast channels (services) are provided where the same content isbroadcast to multiple subscribers that share the available bandwidth.The narrowcast channels (services) are provided where the content issent to a single subscriber through a dedicated link, and thus, thesubscriber does not share the bandwidth with other subscribers. The fullRF load of the second DSRF signal (a.k.a. full load DSRF signal)includes a full bandwidth of the DS signal. Accordingly, the entirebandwidth of the DSRF signal is extended from the first service area tothe second service area. In one implementation, the full load DSRFsignal is dependent on the bandwidth of a standard data over cableinterface specification (DOCSIS). For example, DOCSIS 3.1 standardexpands available bandwidth in the network to 1.218 Ghz and then to1.794 Ghz. In another example, the DOCSIS 3.1 has orthogonal frequencydivision multiplexing (OFDM) channel over the entire spectrum availablefor downstream and upstream communication.

Referring to step 502, a full load DSRF signal is received. At step 504,the full load DSRF signal is pre-amplified for power level adjustment.In one implementation, the pre-amplification functions to convert a lowpower radio frequency signal to a high power radio frequency signal. Assuch, the pre-amplification tunes the full load DSRF signal to nominalamplitude level. In one implementation, a configurable gain in amplitudeis achieved depending on requirements. Then, at step 506, thepre-amplified full load DSRF signal is equalized to keep the power levelconstant over the entire bandwidth (gain flatness). In oneimplementation, the equalization is performed to flatten the frequencyresponse of the full load DSRF signal at a nominal frequency. In oneimplementation, a specific level of flatness/tilt over a bandwidth ofinterest is achieved. Then at step 508, linearization is performed tothe full load DS RF signal to compensate for RF pre-distortion in thefull load DSRF signal to improve the non-linear behavior of the RF andto compensate for the fiber dispersion in the optical link between thefirst service area and the second service area. In one implementation,an RF gain is controlled (automatic gain control) over the link. Asdiscussed above, the optical link is a fiber added between an MDU CPEincluding the RFoG extender of the first service area and the MDU CPE ofthe second service area to extend the DS signal to the second servicearea. Since, the DSRF signal is being transmitted to a longer fiberdistance due to the DS RF signal being extended to the second servicearea, the linearization configures the pre-distortion and fiberdispersion for the optical link in order to compensate for the opticalfiber non-linearity in the DS signal. Then at step 510, the linearizedfull load DSRF signal is amplified to amplify the DSRF signal to the RFlevel desired at the second service area. Then at step 512, implementfiber linearization to the amplified full load DSRF signal in order toensure good signal quality for the extension of the DSRF signal. In oneimplementation, a good signal quality is achieved for a specific fiberlink distance. The fiber linearization functions to further reduce thenon-linearity in the optical link. Some examples of the non-linearity inthe optical fiber may include simulated scattering, self-phasemodulation, cross-phase modulation etc. In one implementation, thenon-linearity is reduced for a specific fiber link distance.

FIG. 5B is a flow chart 520 illustrating another implementation of theRF processing 520 of the DSRF conditioning circuit 418 performed on achannel segmentation RF load of the second DSRF signal 403 b of FIGS. 4Aand 4B. In one implementation, the RF processing 520 is programmableover the DSRF conditioning unit 418. The channel segmentation RF load ofthe second DSRF signal (a.k.a. channel segmented DSRF signal) includesselected channel bandwidth of the DSRF signal. Accordingly, a selectedchannel bandwidth of the DSRF signal is extended from the first servicearea to the second service area. In one implementation, the channelsegmented DSRF signal is dependent on the bandwidth of the standardDOCIS. For example, DOCSIS 3.1 utilizes OFDM channels, which occupy afrequency range spectrum from 24 Mhz to 192 Mhz.

Referring to step 522, a full load second DSRF signal is received. Atstep 524, one or more channels in the bandwidth of the full load secondDSRF signal is filtered to be selected for the RFoG extension. In oneimplementation any of the OFDM channel on the DSRF bandwidth isfiltered, In one example, the selected channel is a specific orthogonalfrequency division multiplexing (OFDM) channel in which the RF channelshaving frequency from 24 Mhz to 192 Mhz in the OFDM are selected. Atstep 526, the selected channel of the full load DSRF signal is downconverted to a lower bandwidth of the selected channel such that the DSsignal begins at a lower bandwidth of the selected channel. In oneimplementation, the selected channel DSRF signal is down converted to apotentially lowest frequency in the selected channel. In oneimplementation any OFDM channel on the DSRF bandwidth is down converted.

At step 528, a down converted selected channel of the full load DSRFsignal is pre-amplified for power level adjustment. As discussed above,the pre-amplification functions to convert a low power radio frequencysignal to a high power radio frequency signal. As such, thepre-amplification tunes the DS signal to nominal amplitude level. In oneimplementation, a configurable gain in amplitude is achieved dependingon requirements. Then, at step 530, the pre-amplified selected channelof the full load DSRF signal is equalized to keep the power levelconstant. As discussed above, the equalization is performed to flattenthe frequency response of the selected channel of the DS signal at anominal frequency. In one implementation, a specific level offlatness/tilt over a bandwidth of interest is achieved. Then at step532, the equalized selected channel of the full load DSRF signal islinearized to compensate for RF pre-distortion in the selected channelDSRF signal to improve the non-linear behavior of the RF and tocompensate for the fiber dispersion in the optical link between thefirst service area and the second service area. In one implementation,an RF gain is controlled (automatic gain control) over the link. Then atstep 534, the linearized selected channel of the full load DSRF signalis amplified to amplify the DSRF signal to the RF level desired at thesecond service area. At step 536, a fiber linearization is implementedto the amplified selected channel of the full load DSRF signal after theamplification in order to ensure good signal quality for the extensionof the DSRF signal. In one implementation, a good signal quality isachieved for a specific fiber link distance. As discussed above, thefiber linearization functions to further reduce the non-linearity in theoptical link. Some examples of the non-linearity in the optical fibermay include simulated scattering, self-phase modulation, cross-phasemodulation etc. In one implementation, the non-linearity is reduced fora specific fiber link distance.

Referring back to FIG. 4A, the output of the DSRF conditioning circuit418 is a second DSRF signal 403 c (one of fiber linearized full loadDSRF signal or fiber linearized selected channel DSRF signal), which istransmitted to the RFoG extender optical TX 422. The RFoG extenderoptical TX 422 converts the second DSRF signal 403 c from the RF domainto an optical domain into the second DS optical signal. The second DSoptical signal is transmitted by the RFoG extender WDM 426 to the secondservice area (for example, the second service area 310 in FIG. 3) via afiber link 429. As such, the DS optical signal is extended from the MDUCPE 400 of a first service area (for example the first service area 308in FIG. 3) to a MDU CPE (not shown) of a second service area (forexample, the second service area 310 in FIG. 3).

The MDU coaxial network 412 sends a USRF signal 405 as an input to thediplexer 410. The diplexer 410 filters the USRF signal 405 in the lowfrequency mode resulting in a USRF signal 405 a and transmits to theUSRF conditioning circuit420. An US optical signal is received by theRFoG extender WDM filter 426 from a second service area (not shown) viathe fiber link 429 The RFoG extender WDM filter 426 filters the USoptical signal and sends it to the RFoG extender optical RX2 424, whichconverts it into RF domain into a USRF signal 405 b and transmits it tothe USRF conditioning circuit 420. The USRF conditioning circuit 420combines both the USRF signals 405 a and 405 b processes the combinedUSRF signal to generate USRF signal 405′. As such, the US RF signal isextended from a MDU CPE (not shown) of a second service area (forexample, the second service area 310 in FIG. 3) to the head end (e.g.402 in FIG. 4 or 302 in FIG. 3). In one implementation, the US RFconditioning circuit 420 functions similar to the DS RF conditioningcircuit 418 as described above. In one implementation, the USRFconditioning circuit 420 functions to multiplex all the USRF signals,maintains stable gain of the RF path, equalizes the USRF signal toflatten the RF gain over the entire USRF bandwidth, attenuates tocontrol RF gain over the link, improves signal quality and compensatesfor fiber dispersion and stimulate brillouin scattering (SBS))suppression to reduce fiber non-linearity. The USRF conditioning unit420 may also filter out desired channels and down convert the desiredchannels. In one implementation, the USRF conditioning circuit 420 maybe designed for direct modulation (such as multi-carrier modulationtechniques, e.g. orthogonal frequency division multiplexing (OFDM)) orfor external modulation with a difference residing in the pre-distortionand the bias connections for the external modulation. The US RFconditioning circuit 420 may further function to condition the modulatedsignal into a format that can be sent through the network.

In one implementation, for processing of the USRF signal is similar tothe processing described with respect to FIGS. 5A and 5B above for thefull load DSRF signal and the channel segmented DSRF signalrespectively. In one implementation, the output of the USRF conditioningcircuit 420 is a processed USRF signal 405′, which includes flatness ofthe frequency response, configuration of the pre-distortion and fiberdispersion for the optical link to compensate for the optical fibernon-linearity in the US signal and amplification in the US signal toachieve a very good quality US Signal with the expected optical powerlevel based on the network extension distance. The USRF signal 405′ isconverted back into optical domain by the RFoG optical TX1408 as an USoptical signal and send to the RFoG WDM filter 404 to be transmitted tothe head end 402. Also, shown in FIG. 4A is a link from the RFoG WDMfilter 404 to couple with a PON (not shown) to provide PON cableservices outside of the MDU CPE device 400.

FIG. 6A illustrates an example of a block diagram of a RFoG architecture600, which functions to extend a complete full RF load of the DS signal(for example second DS RF signal 403 b of FIG. 4A) to multiple MDU CPEdevices. The RFoG architecture 600 is similar to the RFoG architecture300 of FIG. 3 with the exception that the RFoG architecture 600 includesadditional new remote service area (a.k.a. third service area) 640 andmultiple MDU CPEs 612 a-612 n including their corresponding RFoGextenders 630 a-630 n in the first service area 608. The RFoG extenders630 a-630 n is the same as the RFoG extender 330 provided in FIG. 3. Asshown, each of the MDU CPEs 612 a-612 n including the corresponding RFoGextenders 630 a-630 n in the first service area 608 are coupled to theoptical node 606, which is coupled to the head end 602.

In one implementation, the head end 602 transmits a full RF load of theDS signal to the optical node 606. As discussed above, in oneimplementation, the full RF load of the DS signal includes broadcast andnarrowcast channels. The broadcast channels (services) are providedwhere the same content is broadcast to multiple subscribers that sharethe available bandwidth. The narrowcast channels (services) are providedwhere the content is sent to a single subscriber through a dedicatedlink, and thus, the subscriber does not share the bandwidth with othersubscribers. In this example shown in FIG. 6A, the full RF load of theDS signal is in the range of 5 MHz to 1794 MHz. The Optical Node 606transmits all of the full RF load of the DS signal to each of the MDUCPEs 612 a-612 n in the first service area 608. In one implementation,the RFoG extenders 630 a-630 n in their corresponding MDU CPEs 612 a-612n perform the RF processing 500 as discussed with respect to FIG. 5Aabove, which provides capability for each of the RFoG extenders 630a-630 n to transmit the full RF load of the DS signal to the second andthe third service areas 610 and 640 respectively. In one implementation,as shown, each of the RFoG extenders 630 a-630 c not only provide fullRF load of the DS signal to their corresponding MDU CPE 612 a-612 c inthe first service area 608 but also extend the full RF load of the DSsignal to the corresponding MDU CPE 614 a-614 c in the second servicearea 610. In one implementation, the RFoG extender 630 n serves toprovide full RF load of the DS signal to the corresponding MDU CPE 614 nof the first area 608 and extend the full RF load of the DS signal fromthe first service area 608 to a corresponding MDU CPE 642 n of the thirdservice area 640. In one implementation, the RFoG extenders 630 a-630 nperform the RF processing of the US signal (as described above withrespect to US conditioning circuit), which provides capability for eachof the RFoG extenders 630 a-630 n of the first service area 608 toreceive the US signal from the second and third service areas 610 and640 respectively, As such, the US RF signals are extended from thesecond and the third service areas 610 and 640 respectively to the headend 602.

Although the RFoG extenders 630 a-630 c are shown to be implemented inthe MDU CPEs of the first service area 608 as illustrated in FIG. 6, itshould be apparent that the RFoG extenders 630 a-630 c may beimplemented in the MDU CPE (for example, the MDU CPE 614 a-614 c) of thesecond service area 610. Similarly, the RFoG extender 630 n may beimplemented in the MDU CPE (for example, the MDU CPE 642 n) of the thirdservice area 640. In one implementation, both the first and the secondservice areas 608 and 610 respectively may include the MDU CPEs with theRFoG extender(s) 630 and third service area 640 include the MDU CPE 642n without the RFoG extender. In another implementation, the first andthe third service areas 608 and 640 respectively may include the MDUCPEs with the RFoG extender(s) 630 and the second service area includesthe MDU CPE without the RFoG extender. In a further implementation, thesecond and the third service areas 610 and 640 respectively may includethe MDU CPEs with the RFoG extender(s) 630 and the first service area608 includes the MDU CPE without the RFoG extender.

In one implementation, the RFoG extender would be selected to be placedin the MDU CPE of a service area among a plurality of service areaswhere the RFoG is to be extended to the other service area (remote fromthe plurality of service areas), for example, based on network coveragedistance between each of the plurality of the service areas and theanother service area. The service area among the plurality of serviceareas having the minimal network coverage distance may be selected forthe placement of the RFoG extender. In the example of the RFoGarchitecture 600 illustrated in FIG. 6A, network coverage distance fromthe first service area 608 to the third service area 640 is smaller thanthe network coverage distance from the second service area 610 to thethird service area 630. As such, the RFoG extender 630 is implemented inthe MDU CPE (for e.g. the MDU CPE 612 n) of the first service area 608as shown in FIG. 6A. In another example (not shown), the networkcoverage distance from the first service area 608 to the third servicearea 640 is larger than the network coverage distance from the secondservice area 610 to the third service area 640. In this example, theRFoG extender would be implemented in the MDU CPE 614 n of the secondservice area 610

FIG. 6B illustrates an example of a block diagram of a RFoG architecture650, which functions to extend a channel segmentation of the RF load ofthe DS signal (for example second DS RF signal 403 b of FIG. 4A) tomultiple MDU CPE devices. The RFoG architecture 650 is similar to theRFoG network 600 of FIG. 6A except that the RFoG architecture 650extends selected channels in the bandwidth of the full RF load of the DSsignal for extension while the RFoG architecture 600 extends the full RFload of the DS signal. In one implementation, the head end 602 transmitsa full RF load of the DS signal to the Optical Node 606. In this exampleshown in FIG. 6B, the full RF load of the DS signal is in the range of 5MHz to 1794 MHz. The Optical Node 606 transmits all of the full RF loadof the DS signal to each of the MDU CPEs 612 a-612 n including theircorresponding RFoG extenders 630 a-630 n in the first service area 608.The RFoG extenders 630 a-630 n perform the RF processing 520 asdiscussed with respect to FIG. 5B above and thus, each of the RFoGextenders 630 a-630 n is capable of transmitting the processed selectedchannel in the bandwidth of the full RF load of the DS signal to thesecond and the third service areas 610 and 640 respectively. In oneexample, the selected channel is an orthogonal frequency divisionmultiplexing (OFDM) channel in which the RF channels in the OFDM areselected. Each of the channels 1-8 shown in FIG. 6B for example include192 MHz OFDM channels. In one example, as shown in FIG. 6B, each of thechannels 1, 2, 3, 5 and 7 of the full RF load of the DS signal areselected and down converted and further processed as described abovewith respect to the RF processing 620 and then are capable to betransmitted to second and third service areas 610 and 640 respectively.In one implementation, one of the advantages of selecting specificchannels to be filtered and down converted before the transmission forthe network extension is a reduction in channel bandwidth. Thisreduction in the channel bandwidth results in reduction in complexityfor the DSRF conditioning circuit for gain, flatness, predistortion,etc. Further, the signal quality can be achieved easier compared to thetransmission of the full RF load (higher bandwidth). As illustrated inFIG. 6B, the RFoG extender 630 a in the MDU CPE 612 a extendstransmission of channel 1 to the corresponding MDU CPE 614 a of thesecond service area 610. Similarly, the RFoG extender 630 b in the MDUCPE 612 b extends transmission of channel 5 to the corresponding MDU CPE614 b of the second service area 610 and the RFoG extender 630 n in theMDU CPE 612 n extends transmission of channel 2 to the corresponding MDUCPE 642 n of the third service area 640. In one implementation, the RFoGextender 630 c of the MDU CPE 612 c combines channels 3 and 7 andtransmits them together to the corresponding MDU CPE 614 c of the secondservice area 610. In one implementation, by combining the two channels,less bandwidth is utilized for their transmission to the service areas.

FIG. 7 illustrates an example of a block diagram of a CPE RFoGarchitecture 700, which functions to extend optical network of both fullRF load of the DS signal and the channel segmentation of the RF load ofthe DS signal in an indoor environment. An example of the indoorenvironment is a single family home. As shown, the CPE RFoG architecture700 may include multiple devices such a first device 718 a, a seconddevice 718 b, a third device 718 c and a fourth device 718 d andextension capability of the RFoG is provided to the multiple devices 718a-718 d. The multiple devices may include, but not limited to, atelevision, a personal computer, a laptop, a smart phone or combinationsthereof. In one implementation, a bandwidth requirement is set up forone or more of the multiple devices 718 a-718 d. As shown, an opticalnode 704 is optically coupled to a head End 702 to receive DS andtransmit US signals. The optical node 704 is coupled to a CPE 712 aincluding an RFoG extender 730, which receives a full RF load of the DSsignal. In one implementation, the RFoG extender 730 functions to extendthe full RF load of the DS signal from the CPE 712 a to the first andsecond devices 718 a and 718 b respectively. A second RF splitter 714 iscoupled to the CPE 712 a to split the full RF load of the DS signalbetween the first and the second device 718 a and 718 b respectively. Inone implementation, the RFoG extender 730 functions to extend selectedchannels in the bandwidth of the full RF load of the DS RF signal to thethird and fourth devices 718 c and 718 d respectively. In one example,channels 7 and 8 are selected and down converted and further processedas described above with respect to the RF processing 620 and then aretransmitted to an optical splitter 716, which splits the channels suchthat channel 7 is extended to the third device 718 c and channel 8 istransmitted to the fourth device 718 d or vice versa. As such, bandwidthcapability of a CPE is extended by the RFoG extender 730 by transmittingeach of the separate selected channels into their respective devices.Accordingly, applications running in each of the third and fourthdevices 718 c and 718 d do not interfere with each other.

FIG. 4B depicts an example of a schematic diagram of a MDU CPE device440. The MDU CPE device 440 is similar to the MDU CPE 440 as illustratedin FIG. 4A with the exception that the MDU CPE 440 includes a PONextender 441 integrated within the MDU device 440 such that one MDU CPEmay support both the traditional cable service (Coaxial) and the PONservice. The PON extender 441 is same as the PON extender 241 of FIG.2B. As shown, the PON extender 441 is also coupled to the RFoG/PONextender WDM filter 428, which extracts the PON signals (DSPON opticalsignal having the wavelength of 1490 nm and USPON optical signal havingthe wavelength of 1310 nm). The RFoG/PON extender WDM filter 428transmits the DSPON optical signal to the second service area via thefiber 1 ink429, As such, the DSPON signal is extended from the MDU CPE440 of a first service area (for example the first service area 308 inFIG. 3) to a MDU CPE (not shown) of a second service area (for example,the second service area 310 in FIG. 3). The USPON signal is received bythe RFoG/PON extender WDM filter428 from a second service area (notshown) via the fiber 1 ink429, which is transmitted to the PON extender441. As such, the USPON signal is extended from the second service areavia the fiber link 429 to the head end 402. Accordingly, the MDU CPEdevice 420 not only provides capability to receive and extend thetraditional cable service of the MCU Coaxial Network 412 but alsoprovides the capability to receive and extend the PON service of thelocal PON network 452. In one implementation, the MDU CPE 440 of FIG. 4Bfunction to receive and extend the RFoG services and at the same timefunction to receive and extend the PON services.

As disclosed herein, the ability to extend RFoG network coverage with anRFoG extender reduces or prevents the need to install any additionalnode or optical amplifiers, thus providing for a more simple and costeffective RFoG system with reduced power consumption. The RFoG extenderis flexible enough to be implemented at a specific MDU CPE as needed,and the MDU CPE with the RFoG extender may be implemented on specificservice areas where network extensions are beneficial. Furthermore, withrespect to network topology, the RFoG extender at a customer locationMDU CPE allows for the possibility to migrate the HPON network from asingle level optical fiber tree topology (Node to CPEs) to a multi-levelfiber tree and branch network topology (Node to CPEs to other CPEs).Additionally, by processing the US and DS signals, the quality of thesesignals are not comprised with an implementation of the RFoG extender.

It will be understood that the terms and expressions used herein havethe ordinary meaning as it is accorded to such terms and expressionswith respect to their corresponding respective areas of inquiry andstudy except where specific meanings have otherwise been set forthherein. Relational terms such as first and second and the like may beused solely to distinguish one entity or action from another withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions. The terms “comprises,” “comprising,”“includes,” “including,” or any other variation thereof, are intended tocover a non-exclusive inclusion, such that a process, method, article,or apparatus that comprises a list of elements does not include onlythose elements but may include other elements not expressly listed orinherent to such process, method, article, or apparatus. An elementpreceded by “a” or “an” does not, without further constraints, precludethe existence of additional identical or similar elements in theprocess, method, article, or apparatus that comprises the element.

The term “coupled” as used herein refers to any logical, physical orelectrical connection, link or the like by which signals produced by onesystem element are imparted to another “coupled” element. Unlessdescribed otherwise, coupled elements or devices are not necessarilydirectly connected to one another and may be separated by intermediatecomponents, elements or communication media that may modify, manipulateor carry the signals. Each of the various couplings may be considered aseparate communications channel.

In one or more examples, the functions described herein may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium and executed by a hardware-based processingunit. Computer-readable media may include computer-readable storagemedia, which corresponds to a tangible medium such as data storagemedia, or communication media including any medium that facilitatestransfer of a computer program from one place to another, e.g.,according to a communication protocol. In this manner, computer-readablemedia generally may correspond to (1) tangible computer-readable storagemedia which is non-transitory or (2) a communication medium such as asignal or carrier wave. Data storage media may be any available mediathat can be accessed by one or more computers or one or more processorsto retrieve instructions, code and/or data structures for implementationof the techniques described in this disclosure. A computer programproduct may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinter-operative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent concepts.

1. A radio frequency over glass (RFoG) system comprising: an opticalnode; and an RFoG extender, residing in a first service area and coupledto the optical node to: transmit an upstream (US) radio frequency (RF)signal to a head end; receive a downstream (DS) RF signal from the headend; and extend the DS RF signal to the second service area, wherein thesecond service area is different from the first service area and thesecond service area is remote from the first service area.
 2. The RFoGsystem of claim 1 wherein the RFoG extender resides in a first customerpremises equipment (CPE) of the first service area and the DSRF signalis extended from the first CPE of the first service area to a second CPEof the second service area.
 3. The RFoG system of claim 1 wherein theRFoG extender resides in a first multi-dwelling customer premisesequipment (MDU CPE) of the first service area and the DSRF signal isextended from the first MDU CPE of the first service area to a secondMDU CPE of the second service area.
 4. The RFoG system of claim 1wherein the RFoG extender comprises a first RF splitter that divides theDSRF signal into a first DSRF signal and a second DSRF signal.
 5. TheRFoG system of claim 4 wherein the RFoG extender to extend the USRFsignal from the second service area to the head end.
 6. The RFoG systemof claim 4 wherein the RFoG extender comprises a DSRF conditioningcircuit to process the second DSRF signal.
 7. The RFoG system of claim6, wherein the RFoG extender further comprises an optical transmitter toconvert the processed second DSRF signal into an optical domain and sendthe converted DS optical signal to the second service area.
 8. The RFoGsystem of claim 6 wherein: the second DSRF signal is a full load DSRFsignal, wherein the full load DSRF signal comprises broadcast andnarrowcast channels, and to process the full load DSRF signal, the DSRFconditioning circuit is configured to: pre-amplify the full load DSRFsignal to adjust a power level; equalize the pre-amplified full loadDSRF signal to maintain the power level at a constant value; linearizethe equalized full load DSRF signal to compensate for RF pre-distortionin the full load DSRRF signal and fiber dispersion in an optical linkbetween the first service area and the second service area, wherein theoptical link is configured to transmit the extended DSRF signal to thesecond service area; amplify the linearized full load DSRF signal to aRF level of the second service area; and implement fiber liberalizationto the amplified full load DSRF signal.
 9. The RFoG system of claim 6wherein: the second DSRF signal is a full load DSRF signal, wherein thefull load DSRF signal comprises broadcast and narrowcast channels; andto process the full load DSRF signal, the DSRF conditioning circuit tois to: filter a channel among a plurality of channels of the full loadDSRF signal selected to provide a link for extending the second DSRFsignal to the second service area; down convert the selected channel ofthe full load DSRF signal to a lower bandwidth; pre-amplify the downconverted selected channel of the full load DSRF signal to adjust apower level; equalize the pre-amplified selected channel of the fullload DSRF signal to maintain power level at a constant value; linearizethe equalized selected channel of the full load DSRF signal tocompensate for RF pre-distortion in the selected channel of the fullload DSRF signal and fiber dispersion in an optical link from the firstservice area to the second service area, wherein the optical link isconfigured to provide the extended DSRF signal to the second servicearea; amplify the linearized selected channel of the full load DSRFsignal to a level of the second service area; and implement fiberlinearization to the amplified selected channel of the full load DSRFsignal.
 10. The RFoG system of claim 9 wherein: the RFoG extenderresides in a first multi-dwelling customer premises equipment (MDU CPE)of the first service area, and the processed channel segmented DSRFsignal is extended from the first MDU CPE of the first service area to asecond MDU CPE of the second service area, wherein the processed channelsegmented DSRF signal comprises two channels among the plurality ofchannels selected to be extended to the second service area, and the twoselected channels comprise a first selected channel and a secondselected channel different from the first selected channel such that theprocessed channel segmented DSRF signal is transmitted to the second MDUCPE in the second service area on a combination of the first selectedchannel and the second selected channel.
 11. The RFoG system of claim 9wherein: the RFoG extender resides in a first customer premisesequipment (CPE) of the first service area, and the processed channelsegmented DSRF signal is extended from the first CPE of the firstservice area to a second CPE of the second service area, wherein theprocessed channel segmented DSRF signal comprises two channels among theplurality of channels selected to be extended to the second servicearea, and the two selected channels comprise a first selected channeland a second selected channel different from the first selected channelsuch that the processed channel segmented DSRF signal is transmitted tothe second CPE in the second service area on a combination of the firstselected channel and the second selected channel.
 12. The RFoG system ofclaim 11 wherein: the second service area comprises a second RF splitterto split the combination such that the processed channel segmented DSRFsignal is transmitted to a first device in the second CPE of the secondservice area on the first selected channel, wherein the second RFsplitter is different from the first RF splitter; and the processedchannel segmented DSRF signal is transmitted to a second device in thesecond CPE of the second service area on the second selected channel,wherein the second device is different from the first device.
 13. TheRFoG system of claim 1 wherein the USRF signal is a first USRF signaltransmitted from a coaxial network and a second USRF signal transmittedfrom a second service area.
 14. The RFoG system of claim 12 furthercomprising a US conditioning circuit, wherein the US conditioningcircuit to combine the first USRF signal and the second USRF signal intoa combined USRF signal.
 15. The RFoG system of claim 14 wherein thecombined USRF signal is one of a full load USRF signal or a channelsegmented USRF signal and the US conditioning circuit to process one ofthe full load USRF signal or the channel segmented USRF signal.
 16. TheRFoG system of claim 1 further comprising a link coupled to the opticalnode to send and receive a passive optical network (PON) signal from alocal PON network, wherein the local PON network is different from thecoaxial network.
 17. A radio frequency over glass (RFoG) systemcomprising: an optical node; an RFoG extender residing in a firstservice area and coupled to the optical node to: transmit an upstream(US) radio frequency (RF) signal to a head end; receive a downstream(DS) RF signal from the head end; and extend the DS RF signal to thesecond service area, wherein the second service area is different fromthe first service area and the second service area is remote from thefirst service area; and a passive optical network (PON) extenderresiding in the first service area and coupled to the optical node to:transmit a US PON signal to a local PON network; receive a DS PON signalfrom the local PON network; and extend the DS PON signal to the secondservice area.
 18. The RFoG system of claim 17 wherein: the PON extenderresides in one of a first customer premises equipment (CPE) or a firstmulti-dwelling customer premises equipment (MDU CPE) of the firstservice area, and the DS PON signal is extended from the one of thefirst CPE or the first MDU CPE of the first service area to one of asecond CPE or a second CPE of the second service area.
 19. The RFoGsystem of claim 17 wherein: the RFoG extender to extend the USRF signalfrom the second service area to the head end; and the PON extender toextend the US PON signal from the second service area to the head end.20. The RFoG system of claim 17 wherein the DSRF signal and the DS PONsignal are simultaneously extended to the second service area.